Motor shaft marking
 

Just picked up a used Reedy motor - it has the numbers 275 on the pinion flat. What is this?

Motor is supposed to be a 7.5t - I'm hoping it isn't a 27.5t !

Also, what's the best way to clean this motor thoroughly? Same for the ESC I've got with it, there's a sandy/muddy residue on it.

https://cimg5.ibsrv.net/gimg/www.rct...c986094c6b.jpg

The number on the rotor isn't related to the number of turns of the stator. It's an identifier for the rotor itself, they come in different sizes.

Electrical spray for the motor and to get excess stuff off the ESC, and if there's still divided stubborn stuff on the ESC, isopropyl alcohol and a toothbrush.

275 rotor

That part number is how you tell what rotor is in the motor, as you can change them to tweak how the motor performs. I wanna say I ran a softer 272 rotor in my 2wd buggy when I ran the M3 reedys. As an example.

The rotor in a brushless motor is just magnets though right? Looking at the link you posted - 275 isn't there - each number though seems to refer to a number of turns - maybe that's just the default rotor for the motor?

Do you know what physically changes between the rotors?

Rotor strength, rotor length, rotor diameter, rotor internal diameter.

The number has nothing to do with the number of turns of the stator.

Their link took me here. Part number is 275. Dimensions are 12.5 outer diameter, 5.0 inner diameter, 25.3 length.

https://cimg6.ibsrv.net/gimg/www.rct...eb3cdd63f7.png

Think I misread this table at the link. I figured the part number for the rotor matched a number of turns, but it seems it's used on all of these motors.
https://cimg1.ibsrv.net/gimg/www.rct...674a4b0f73.png

Plus there isn't a single 27.5T motor in existence that I'm aware of. 25.5T is as far as it gets in 540 sized brushless systems.

I'm definitely leaning on old brushed knowledge, the game's changed!

Hey Alex - I didn't realise how old this motor was when I bought it - it seems it could be as old as 2015.

I'm going to be running it in 1/10th modified stadium truck - anything I should be aware of? What would one expect from an older motor?

At the end it is just an easy look by the user or technical inspection what rotor is used.

Should be absolutely fine for mod truck. Just lookup the gearing chart in the manual. Rebuilding the ball diff and breaking it in for 20 min and setting your slipper right is all you'll have to worry about. Mod motors will last for years since they dont run as hot as stock motors.

Depending on your skill level, and if the motor is still good, it should be pretty competitive for you. I would get some electric motor cleaner and take the motor apart to clean it. Also, make sure to lube the bearings really good.